1. Field of the Invention
The invention relates to a locking device for a safety belt with a belt lock and a plug-in tongue fastened to the belt-end, whereby the tongue can be engaged with an engagement edge by at least one latch which is movable transversely to the plug-in direction of the plug-in tongue.
2. Description of the Prior Art
In the known locking devices of this type, in which either the plug-in tongue is provided with a detention opening into which the block-like latch falls when the tongue is plugged into the belt lock, or in which the plug-in tongue is made in a T-shape, and acts in conjunction with two latching elements which engage behind the free T-legs, the engagement edge of the tongue is essentially parallel to the locking edge of the latch working in conjunction with the tongue, so that the two edges butt against each other with their whole area when the safety system is not heavily loaded. However, in operation, particularly in case of a crash, i.e. if a very great pulling force acts on the belt end, and thereby on the plug-in tongue, one can, as a rule, detect a deformation of the originally straight engagement edge of the plug-in tongue, which is often connected with a slight oblique position of the plug-in tongue. The result of this deformation is that the mentioned edges do not contact each other with their full areas, but touch each other at one point, i.e. with very high stress on a small area, so that great shear forces are acting on the plug-in tongue, and can thereby nullify the safety function of the safety system.